Kinematics of Special Relativity  

General Concepts > s.a. lorentz group; spacetime models; time; [Reference Frame].
* Interval: A useful expression is ds2 = –c2 t1t2, where... @ Ohanian & Ruffini 94, p 70.
* Boost: A transformation of coordinates given by t' = t cosh u + x sinh u, x' = t sinh u + x cosh u, for a boost along the x-axis (with tanh u = ); The coordinates y and z in this case are unchanged, and the boost vector field is

v:= x /t + t /x ;

In general relativity, the corresponding conserved quantity (center of energy, > see conserved quantities) for asymptotically flat spacetimes is

M(N) = infty [N(a qbcb qac) – N,a (qbcfbc) + N,b (qacfac)] qacqbd dSd .

* Time dilation: T = T0; Argue with bouncing photon clock; First tested in 1938 to within 1% of predictions in an experiment by Herbert Ives and G R Stilwell; Verified with cosmic ray muon decays and with GPS tests; 2007, best measurement by Gwinner et al has accuracy quantified by a "Mansouri-Sexl parameter" of less than 8.4 10–8.
* Length contraction: L = –1L0; Argue based on time dilation and L/T0 = L0/T (can be illustrated with long car in garage); > s.a. Lorentz-Fitzgerald Contraction.
* Velocities: Addition, u = (v1+v2)/(1+v1v2/c2) – neither commutative nor associative due to the presence of Thomas precession; Four-velocity, um = dxm/d.
* Doppler shift: Components of vectors normal to are invariant, so k' perp = kperp; for other ones,

k' 0 = (k0 · k) ,   k' 1 = (k1k0) ;
for light   ' = (1–cos) ,   tan' = sin/[(cos)] .

@ Transformations: Brehme AJP(62)jul [Lorentz and Galilei, geometrical]; Lévy-Leblond AJP(76)mar, Lévy AJP(07)jul [derivation]; Janssen SHPMP(09) [kinematical vs dynamical explanations].
@ Length contraction: Rindler AJP(61)jun [paradox]; Nikolic AJP(99)nov-phy/98 [accelerated rod]; Pierce AJP(07)jul [and lock and key paradox]; Redzic EJP(08) [interpretations].
@ Appearance of objects: Penrose PCPS(59) [sphere]; Terrell PR(59); Weisskopf PT(60)sep; in Van Bladel 84; Peres AJP(87)jun; Blackman EJP(98)ap/97; Field AJP(00)apr; Morava a0804 [in terms of groups].
@ Time dilation: Bohm & Hiley AJP(85)aug [and active interpretation of boosts]; Saathoff et al PRL(03) [deviations < 2.2 × 10–7]; Gwinner MPLA(05) [tests, rev]; Harvey & Schücking PT(05)mar [history, and gravitational time dilation]; news pw(07)nov [best measurement yet].

Twin Paradox > s.a. mach's principle.
* Idea: Identical twins who are separated, undergo different accelerations, and are then reunited will have aged differently; Not really a paradox, it is a kinematical special relativity effect due to differences in proper times.
@ General references: Rodrigues & Rosa FP(89), comment Sachs FP(89); Harpaz EJP(90); Debs & Redhead AJP(96)apr [and simultaneity]; Ghosal et al FPL(05) [and equivalence principle], gq/05; Minguzzi AJP(05)sep [explicit formula]; Grøn EJP(06); Kohler FPL(06) [instantaneous turnaround as limit]; Grandou & Rubin a0704/AJP [as a consequence of causality], IJTP(09) [ingredients].
@ In curved spacetime: Dray AJP(90)sep, Barrow & Levin PRA(01)gq [closed universe]; Bansar et al gq/05 [with a compact dimension]; Luminet a0910-in.
@ Variations: Price & Gruber AJP(96)aug; Cranor et al AJP(00)nov, Wortel et al AJP(07)dec-gq [circular]; Iorio FPL(05); Abramowicz et al PRA(07) [on the photon sphere]; Field a0806; Abramowicz & Bajtlik a0905 [version in which the accelerated twin is older].

Accelerated Observers > s.a. Acceleration: Jerk; modified electrodynamics; rotations.
@ General references: Desloge & Philpott AJP(87)mar; Desloge AJP(89)jul [spatial geometry]; Tartaglia & Ruggiero EJP(03)gq; Mashhoon gq/03-in, IJMPD(05)gq/03-in [non-locality]; Pardy gq/03; Alba & Lusanna gq/03 [3+1 view].
@ Rotation, rotating frames: Weber AJP(97)jun [disk]; Tartaglia FP-phy/98 [Ehrenfest paradox]; Herrera NCB(00)gq/99; Bashkov & Malakhaltsev gq/00, gq/01; Klauber gq/01 [frequency and wavelength of light]; Rodrigues & Sharif FP(01) [and Sagnac effect]; Rizzi & Ruggiero FP(02), 03; Peres gq/04/AJP; Klauber FP(07)gq/06; Herrera mp/06 [and Thomas precession]; > s.a. Sagnac Effect; time.
@ Related topics: Gruber & Price AJP(97)oct [t dilation]; Chicone & Mashhoon CQG(04)gq [critical speed c/21/2].

Related Topics > s.a. classical particles [relativistic]; physics teaching.
@ Lorentz "rotations": Terrell PR(59); Weisskopf PT(60)sep; in Taylor & Wheeler 92, 92-93;
@ Simultaneity: Havas GRG(87); Sarkar & Stachel PhSc(99)jun; Giulini gq/00; Mamone FP(01); Janis in(02); Scherr et al AJP(02)dec [student beliefs]; Bolós et al IJTP(02)gq/05 [spacelike vs lightlike]; Minguzzi gq/05-in [in special and general relativity]; > s.a. EPR paradox.
@ Velocity: Lévy-Leblond AJP(80)may; Mermin AJP(83)dec, 90 ch19 [addition]; Sen JMP(90) [relative velocities]; Mathews AJP(05)jan [and acceleration].
@ Other topics: Christodoulou & O'Murchadha CMP(81) [boost problem in general relativity]; Coll & Morales IJTP(92) [frames]; Mermin AJP(97)jun, AJP(98)dec [spacetime diagrams]; Pierceaux phy/04-in [Poincaré's kinematics and light fronts]; Price AJP(05)may-gq [projectiles and pendula]; Dryzek et al AJP(06)jan [lab experiment on E2 = p2c2 + m2c4].
> Other topics: see clocks; Gyrogroup; Pythagorean Theorem; Rapidity; Rigid Body; Superluminal Motion; tachyons.


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